- What are the typical roll dimensions of Poly-Flex® geomembranes?
All Poly-Flex® rolls are 23 feet wide. The roll lengths range from 300 feet up to 1,550 feet depending on the material type and thickness. The gross weights are approximately 3,500 lbs. Please refer to the Material Specification Section.
- What is the permeability of the Poly-Flex® liners?
Poly-Flex® liners have a pseudo coefficient of permeability in the order of 10-13 cm/sec vs. compacted clay at 10-7cm/sec
- What is the moisture vapor transmission rate (MVTR) of the Poly-Flex® liners?
The permeability of Poly-Flex® liners is expressed as the Moisture Vapor Transmission Rate (MVTR) as measured by the ASTM D E96 test method. The property is expressed in
grams/unit area/day. Please refer to inherent properties of polyethylene liners located in Material Specifications.
- What are the advantages of Poly-Flex® smooth edge textured liners?
Our blown-film textured liners have smooth edges and are covered by U.S. Patent Nos. 5,763,047 and 5,804,112. The smooth edges result in easier, more cost-effective, more consistent, and better welding.
- What is the minimum degree of roughness (texturing) a textured liner should have?
The minimum industry standard specification GRI GM13 and GRI GM17, require a minimum Asperity Height of 10 mils for textured HDPE and textured LLDPE geomembranes.
- Are there any adhesives, tapes or glues that are suitable for joining Poly-Flex® liners?
There are no adhesives, tapes or glues that provide a permanent, watertight bond to polyethylene.
- Can Poly-Flex® liners of different thickness or textures be welded to each other?
Yes. Poly-Flex® liners with thickness or texture differences of 20 mils or less can be fusion welded together. Liners with thickness or texture differences of greater than 20 mils should be extrusion welded together.
- Can Poly-Flex® liners of different densities be welded to each other?
Yes. Welding temperature adjustments must be made to achieve a successful weld. When extrusion welding, the lower density welding rod should be used.
- What are the advantages of LLDPE over PVC geomembrane?
The advantages are as follows:
- LLDPE has resistance to a wider range of chemicals as compared to PVC.
- LLDPE is immune from biological attack by microorganisms. Microorganisms could attack PVC and use the plasticizer as a source of food.
- LLDPE is resistant to burrowing animals, PVC is not.
- LLDPE has a lower permeability to methane than PVC.
- LLDPE has a lower moisture vapor transmission rate than PVC.
- LLDPE retains its physical properties due to long-term soil burial. PVC's physical properties diminish in time due to loss of plasticizer.
- LLDPE is resistant to ultra-violet light, PVC is not.
- LLDPE remains flexible at temperatures well below freezing at -25°C. PVC loses its flexibility and becomes brittle at -25°C
- Can Poly-Flex® liners be exposed to sunlight for a long period of time? How long?
Yes. Poly-Flex® liners are specifically formulated and manufactured to resist ultra-violet rays. Therefore, they are suitable for use in exposed applications. The liners are expected to last many decades in exposed applications without any detrimental effect from sunlight.
- What is the elongation or deformation limits of Poly-Flex® HDPE and LLDPE geomembranes before they rupture?
In the multi-axial tension test, ASTM D 5617, the HDPE liners rupture at 15% elongation and the LLDPE liners rupture at 30% elongation.
- Does thickness affect the elongation or deformation limits?
Generally, the elongation property of Poly-Flex® liners is independent of the material thickness. Although thinner liners deform with less pressure, the ultimate elongation at rupture is nearly the same for all gauges.
- Does material thickness influence puncture resistance?
Yes. Thicker liners have higher puncture resistance than the thinner ones.
- What are the temperatures for material that can be contained by Poly-Flex® liners?
Poly-Flex® geomembranes are thermoplastic materials, hence their physical properties are temperature dependent. The material becomes softer and more flexible at higher temperatures and stiffer and stronger at lower temperatures. We specify maximum use temperatures of 160° F for HDPE and 140° F for LLDPE liners.
- What is the cold temperature resistance of Poly-Flex® liners?
Poly-Flex® liners pass the low temperature brittleness test at -70° C (-94° F) according to the ASTM D 746.
- Why do Poly-Flex® liners have wrinkles?
Polyethylene liners expand and contract as the sheet temperature changes. This thermal expansion/contraction will cause the liner to grow or shrink with variance in temperature.
- What is the life expectancy of Poly-Flex® HDPE and LLDPE liners?
The life expectancy of Poly-Flex® liners depends on the environment in which they are installed. Exposure to high temperatures, certain chemicals, constant loads, and adverse site conditions shorten the life of the liners. Under normal conditions, Poly-Flex® HDPE and LLDPE liners are expected to last for many decades.
- Are there any limits on the project size?
No. The project size could vary from a few hundred square feet to millions of square feet of geomembrane.
- Can Poly-Flex® liners be used for potable water applications?
Yes. Poly-Flex® liners do not contain any plasticizers or fillers, and are therefore safe for potable water applications.
- How is the thickness of a liner determined for a specific application?
The liner thickness is determined by the project engineer based on the project site specific conditions.
- Should Poly-Flex® liners be used as reinforcement (structural) membranes?
No. Poly-Flex® geomembranes are not reinforced materials and should not be used as structural membranes to carry loads.
- What are interface friction angles?
Interface friction angles express properties relating to sliding shear resistance between two materials facing each other. This property is used in stability calculations to design a stable liner system.
- How are interface friction angles determined?
The industry standard test method is the ASTM D 5321 "Determining the coefficient of soil and geosynthetic or geosynthetic and geosynthetic friction by the direct shear method".
- What are the temperatures for material that can be contained by Poly-Flex® liners?
Poly-Flex® geomembranes are thermoplastic materials, hence their physical properties are temperature dependent. The material becomes softer and more flexible at higher temperatures and stiffer and stronger at lower temperatures. We specify maximum use temperatures of 160° F for HDPE and 140° F for LLDPE liners.
- What is the cold temperature resistance of Poly-Flex® liners?
Poly-Flex® liners pass the low temperature brittleness test at -70° C (-94° F) according to the ASTM D 746.
- Are Poly-Flex® liners immune to root penetration?
Poly-Flex® liners resist root penetration. However, some vegetation, such as nut grass, could penetrate the liners. We recommend that the subgrade soils be prepared to be free of roots and organic material.
- Are Poly-Flex® liners immune to attack by rodents?
Poly-Flex® liners are generally immune to rodent and insect attack because they contain no plasticizers or scrim source proteins, which are sometimes present in other synthetic liners.
- Can Poly-Flex® liners be installed directly on top of concrete slabs or asphalt pavement?
Yes. Concrete and asphalt slabs must be smooth and have no sharp edges.
- Should wind uplift forces be considered for Poly-Flex® liners installed in exposed applications?
Yes. Wind suction forces can lift exposed liners off the ground and potentially damage them. A ballast system, such as dead weights, sand bags or tubes, anchor trenches, etc. should be considered for all geomembranes installed in exposed applications. For buried applications, the installed liner should be temporarily secured by means of sand bags until covered with soil.
- How much ballast is needed over exposed liners?
The ballast system should be designed to secure the liner in place under the maximum anticipated wind suction pressures for the specific project site. Wind uplift pressures can be as high as 30 psf depending on the project site geometry and wind velocity.
- Can construction equipment be operated directly on the liner?
Equipment that applies less than 2 psi ground pressure can be operated directly on the liner when operated with caution, including no sudden starts, stops or turns.
- What maintenance is required for Poly-Flex® liners after installation?
None. Poly-Flex® liners are maintenance free.
- What procedures should be followed for storing Poly-Flex® liners at a jobsite?
Poly-Flex® liners should be stored on a prepared ground that is free of rocks, roots, debris, or materials that may damage the liner. The rolls should also be stored away from standing water and should not be stacked more than two rolls high.
- How much cover soil is needed before driving on the liner?
The minimum initial lift of cover soil should be determined based on the type of placement equipment, cover soil, and the liner system under consideration. A minimum of 15 - 30 cm (6 - 12 inches), is usually recommended for equipment with light ground pressure of less than 34.5 kPa . A higher initial lift height should be used for proportionally heavier equipment.
- How are Poly-Flex® geomembranes shipped?
Poly-Flex® rolls are shipped by flat-bed trailer trucks. Open- or closed-top containers are used for overseas shipping. Up to 12 full rolls can be shipped per truckload or container.
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